Dental instrument.



O. NEUGEBAUER.

DENTAL INSTRUMENT.

APPLICATION FILED NOV. 19, 1907.

940,351. Patented NOV..16,1909.

UNITED STATES PATENT OFFICE.

or'ro NEUGEBAUER, or trimaran-GERMANY, assrcnon T SIEMENS & HALSKFi A. a,

I or BERLIN, GERMANY, A CORPORATION or GERMANY.

DENTAL INSTRUMENT.

To all whom it may concern:

Be it known that I, O'r'ro NEUGEBA'UER, a subject of the German Emperor, and'resident of Alte Gellerheerstrasse -64, Hanover, Germany, have invented certain new and useful Im rovements in Dental Instruments, of

which the followin is a specification;

' My invention relittes in eneral to dental instruments for working fi lings.

Heretofore such instruments have been formed of steel, agate, ivory and other materials. There have, however, been certain inherent difficulties in this art'which render the used the materials heretofore known for such purposes subject to serious disadvantages. In the first place, the reagents employed in dental practice are injurious to steel, and those materials which could with- .stand the reagents, lacked the necessary toughness and other physical properties which. permitted the manufacture of theinstruments in the most advantageous form.

Furthermore, .it is often necessary. or desir-' .able to work 1n locations Where it has been 25 exceedinglyldiflicult to provide for the 'suitable instruments. For example, the space maybe very limited as in the case of nerve seriously handicapped by the lack of a suitable tool for working it. These fillings are subject to'discoloration when-worked by the instruments heretofore employed. Nu-

merous other difiiculties, well known to those skilled in'this; art are met with and remain unsolvedby the instruments heretofore available.

. .In accordance with'my invention, these instruments" are. constructed of a "material which I haye-found to be peculiarly suited to suchuse and which does away with substantially'all of the diliiculties and limitations of the character above referred to.

This material is tantalum. Pure tantalum or tantalum mixed with iron or with carbon serves these well as pure tantalum, the tantalum with adi This material is extremely culty has been tov urposes and hence reference to tantalum Wll be understood to lndicatc as Serial No. 402,929.

t hard, has a very high meltingpoint, 'reat toughness, the desired flexibility, an re markable elasticity. Especially is the form in which admixtures are present of extreme hardness. It can be rendered harder than steel while still retaining its flexibility,

toughness and elasticity. On the other hand,

tantalum is entirely indifferent to .the reagents used in dentistry, not being attacked by any acids with the exception of hydro fluoric acid and resistant to most basis. Consequently the instruments constructed 1n accordance with my invention may be readily cleaned and disinfected in acid, or may be boiled in soda. water without fear of detriment. It is also superior in its operation, since it retains its cuttingedge' better than steel and. is not so liable to fracture. It does not discolor porcelain or silicate fillings and may be employed for all fillings, even those containing mercury and those just' mentioned; r

- The instruments may be constructed much thinner than similar instruments of steel,

while at the same time they are of equal strength and durability.

. The accompanymg drawing shows a denv Specification of Iiette'rs l'atent. P t t d 1 1909 Application filed November I9, 1907.

tal instrument having a tantalum blade'or operating part constructed in accordance withmy invention. ;x

It is of courseunnecessary to forinthe entire instrument of the material iii-question,

as in many instances only the operatmgpart need be so formed, the other parts being of any suitable material, 1 I

am aware that'tantalum haslb'een employed for certain other pur bees, as 'for example, in electric li hting, but so far as I am aware, I am the rst to point out and use in dental instruments those properties which I have discovered to be so peculiarly suited and by which somany advantages are to be obtained.

I claim: A dental instrument for working fillings having its operative part or parts composed of tantalum.

In testimony whereof I have signed my name to this specification n the presence. of

two witnesses.

I OTTO .NEUGEBAUER; Witnesses LnoeFRAN 's, v 

